The overall objective of this project is to investigate the role of ectomycorrhizae (ECM) and common mycorrhizal networks (CMNs) in facilitating common mycorrhizal networks regeneration in the interior of British Columbia. It is comprised of three studies being conducted by four graduate students of Dr. Suzanne Simard, Dr. Melanie Jones, and Dr. Dan Durall. In the first study, PhD student François Teste is conducting a series of experiments in the IDF zone (1) to examine the influence of advance regeneration size on Douglas-fir seed and seedling regeneration, (2) to examine the influence of green tree distance on Douglas-fir seedling performance, and (3) to determine whether importance of the CMN to Douglas-fir establishment increases with site disturbance. In Francois’ first experiment, Douglas-fir was planted and seeded near established Douglas-fir advance regeneration of different sizes, and in his second experiment, at different proximities to pole-sized trees. In the third experiment, a range of organic matter removal treatments were applied in the border areas of the Long Term Site Productivity study sites near Kamloops (Berch 2000), and advance regeneration were transplanted to these treatments to serve as EM inoculum sources to seedlings being planted in 2005. In the second study, MSc student, Brendan Twieg examined a chronosequence of mixed Douglas-fir – paper birch forests to (1) characterize successional patterns of the below-ground ECM community with increasing age and (2) examine relationships between soil properties and ECM community measures. In 2005-06, Brendan completed his thesis (deliverable attached). Within the same chronosequence study, MSc student Denise Brooks has been addressing a third objective, (3) to determine whether the Douglas-fir ECM fungi on clearcuts are better adapted to those sites than are forest fungi by comparing the phosphatase activity among stands of different ages. In the third study, being conducted by PhD student Justine Karst, the primary objective is to determine the role of ectomycorrhizal fungi in establishment of Douglas-fir across a range of soil moisture conditions. This project has important implications for managing Douglas-fir forests in the IDF and ICH zone of the southern interior of British Columbia. The series of integrated studies are investigating the role of early mycorrhization and CMNs in facilitating Douglas-fir regeneration, which is a problem due to drought in the IDF and competition in the ICH. Our results will help managers design better regeneration and harvesting systems for Douglas-fir, and these will be particularly useful as climate changes.Suzanne Simard.